Freeze-thaw stabilizers for quaternary ammonium compounds



United States Patent 3,274,106 FREEZE-THAW STABILIZERS FOR QUATERNARY AMMONIUM COMPOUNDS Leon D. Smiens, Minneapolis, Minn, assignor to Archer- Daniels-Midland Company, Minneapolis, Minn, a corporation of Delaware No Drawing. Filed Jan. 24), 1964, Ser. No. 338,565 6 Claims. (Cl. 2528.75)

The present invention relates to a method of stabilizing water dispersions of quaternary ammonium compounds. More particularly, this invention relates to a process of imparting freeze-thaw stability to water dispersions of insoluble or partially soluble quaternary ammonium compounds.

Certain quaternary ammonium compounds are known as cationic finishing agents, sometimes referred -to as cationic softeners. They are materials which dissolve or disperse in water, concentrate and orient at interfaces, and ionize in such a manner that the cation includes a hydrocarbon chain of 8 to 2 carbon atoms. These finishing agents are widely used for imparting pliability, softness and drape, particularly to cellulosic fibers, and as after treatment to improve Water fastness of substantive properties and by the efliciency of their softening and lubricating action upon fabrics treated with the same.

In recent years, the cationic fabric softeners have found their largest application in the commercial and home laundry operations. They are also used extensively in the cellulosic finishing market. In laundry operations, the softeners are employed to give an initial softening effect and to reduce fabric harshness and scratchiness. These cationic fabric softeners are used in the after rinse of a laundry operation. They are also known to impart antistatic properties to synthetic fibers such as rayon, nylon, polyester, and polyacrylic fibers.

Fatty quaternary ammonium chloride compounds are among the most desirable softening agents. One problem with these compounds is that they are not stable in water dispersion to freezing and subsequent thawing. These compositions are normally bought and sold by the consumer in relatively dilute water dispersions. When such dispersions are frozen and subsequently thawed, a gel results, destroying the previous fluid characteristic of the water dispersion.

The inability of such quaternary ammonium compounds to withstand freezing required special precautions so as to eliminate the possibility of freezing in transit or storage during cold weather. It was therefore desirable to obtain a means of imparting freeze-thaw stability without excess additions of compositions which are inactive in providing the desired softening effect.

An object of this invention is to provide a compound which imparts freeze-thaw stability to fatty quaternary ammonium chloride compounds. Another object of this invention is to provide a composition which in addition to providing freeze-thaw stabilizing properties, also exhibits a cationic softening effect on fabrics. A further object of this invention is to provide a fatty quaternary ammonium chloride composition which will not gel on freezing and subsequent thawing.

The objects of this invention are accomplished by the composition which comprises a fatty quaternary ammonium chloride compound and a stabilizing amount of dialkyl sulfate salt of a fatty amine.

The composition of this invent-ion provides a freezethaw stable fabric softener composed of a fatty quaternary ammonium chloride compound and the dialkyl sulfate salt of a fatty amine. This composition, surprisingly exhibits the same desirable softening and antistatic properties of the quaternary ammonium chloride compound, without notice of a dilution effect, in addition to having "ice the desired freeze-thaw stability when diluted with water to 3 to 8% solids. Such compositions when sold to the consumer, are normally at concentrations of 5 to 7% solids, the remainder being water, perfume, alcohol and dye.

The addition of the sulfate salt imparts freeze-thaw stability to fatty quaternary ammonium chloride compounds having the formula:

where R is alkyl, arylalkyl or cycloalkyl, saturated or ethylenically unsaturated hydrocarbon chains of 12 to 26 carbon atoms and R and R are the same as R or alkyls of 1 to 8 carbon atoms and R is an alkyl of 1 to 8 carbon atoms. The saturated or ethylenically unsaturated hydrocarbon chains of 12 to 26 carbon atoms are normally fatty chains derived from animal, vegetable or marine sources. Such sources include coconut, tallow, hydrogenated tallow, soya, linseed, safilower, tall, menhaden, and thel-ike. The cycloalkyl groups are similar to the alkyl groups, the difference being the ring structure.

In addition R R and R, can be arylalkyl groups. Arylalkyl groups are those having an aliphatic chain and an aryl group, the aliphatic group being attached to the nitrogen atom.

The short chained alkyl radicals noted as R R and R are alkyl chains of 1 to 8 carbon atoms. They are either saturated or ethylenically unsaturated. Preferably, the radicals are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl,

The fatty quaternary ammonium chloride compounds have cations such as trimethylalkyl, dimethyldia-lkyl, methyltrialkyl, dimethyldiaryl, t-rimethylarylalkyl, and where methyl is substituted for ethyl, propyl, and the like. More specifically, the preferred compounds include dimethyldicoco ammonium chloride, dimethyldisoya ammonium chloride, dimethyl dihydrogenated tallow ammonium chloride, diethyl ditallow ammonium chloride, diethyl dila-uryl ammonium chloride, dimethyl dimyristyl ammonium chloride, and dimethyl hydrogenated tallow benzyl ammonium chloride.

The sulfate salt which imparts the stabilizing effect to the fatty quaternary ammonium chloride compound has the formula:

where R is a saturated or ethylenically unsaturated alkyl of 8 to 26 carbon atoms and R is hydrogen or a saturated or ethylenically unsaturated alkyl of 1 to 26 carbon atoms. The alkyl group of 8 to 26 carbon atoms is a fatty hydrocarbon radical derived from animal, vegetable and marine sources. The alkyl of l to 8 carbon atoms is normally derived from petroleum sources. R and R" are the same or different alkyl groups of l to 8 carbon atoms. The alkyl groups may be straight-chained or branched and preferably are radicals such as methyl, ethyl, isopropyl and butyl.

The sulfate salt is formed by reacting a primary or secondary amine with a dialkyl sulfate to form the corresponding sulfate salt. Examples of preferred dialkyl sulfates which react with primary or secondary amines to form the desired salt include dimethyl sulfate, diethyl sulfate, diisopropyl sulfate and dibutyl sulfate. The reaction proceeds by the equation:

where R R R and R" are as previously defined.

The sulfate salt forms readily when a dialkyl sulfate is mixed with a primary or secondary amine in a molar ratio. It is some times preferred to use slightly less than a mol of alkyl sulfate per mol of amine.

The reaction between the amine and alkyl sulfate can be accomplished at one hundred percent solids by reacting at temperatures above the melting point of the amine. It is preferred, however, to dilute the amine with an inert solvent prior to the addition of the alkyl sulfate. The preferred solvents are water soluble alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and isopropyl alcohol. The reaction with the alkyl sulfate takes place at room temperature and is exothermic. It is also possible to react the amine with an alkyl sulfate while it is in a mixture with a quaternary ammonium chloride compound.

Some of the preferred salts formed in this manner include the dimethyl sulfate salt of coco primary amine, the dimethyl sulfate salt of soya primary amine, the dimethyl salt of tall primary amine, the.dimethyl sulfate salt of dicoco secondary amine, the dimethyl sulfate salt of disoya secondary amine, the dimethyl sulfate salt of dihydrogenated tallow secondary amine, the dimethyl sulfate salt of dilauryl secondary amine, the dimethyl sulfate salt of dimyristyl secondary amine, the diethyl sulfate salt of dicoco secondary amine, the diethyl sulfate salt of disoya secondary amine, the diethyl sulfate salt of dihydrogenated tallow secondary amine, the diethyl sulfate salt of dilauryl secondary amine, the diethyl sulfate salt of dimyristyl secondary amine, the diisopropyl sulfate salt of coco primary amine, the diisopropyl sulfate salt of soya primary amine, the diisopropyl sulfate salt of tall primary amine, the diisopropyl sulfate salt of lauryl primary amine, the diisopropyl sulfate salt of myristyl primary amine, the diisopropyl sulfate salt of hydrogenated tallow primary amine, the diisopropyl sulfate salt of dicoco secondary amine, the diisopropyl sulfate salt of disoya secondary amine, the diisopropyl sulfate salt of ditallow secondary amine, the diisopropyl sulfate salt of dihydrogenated tallow secondary am-ine, the diisopropyl sulfate salt of ditall secondary amine, and the diisopropyl sulfate salt of dilauryl secondary amine. V Freeze-thaw stability is incorporated into a quaternary ammonium chloride compound, as described, by the addition of about 8% to about 50% of the sulfate salt described. The sulfate salt and quaternary ammonium chloride compound are blended by heating the two compounds above their melting points and mixing them in the desired ratio. The exact mechanics of blending the two compounds does not affect their performance as long as the mixing is complete.

The invention will be better understood with reference to the following examples which are illustrations of certain preferred embodiments of the present invention. Unless otherwise indicated, all parts and percentages used herein are by weight.

Example I A freeze-thaw stabilized quaternary ammonium chloride solution was formed by the processes of this invention as follows:

The dimethyl sulfate salt of dicoco secondary amine was prepared by heating the amine to 110 F. and dissolving the dicoco amine in isopropyl alcohol to form a 75% solution. The solution was placed in a reaction vessel equipped with a stirring means, a thermometer, a cooling means and a dropping funnel. The temperature was controlled so as to not exceed 150 F. while an equal molar amount of dimethyl sulfate was slowly metered into the reaction vessel. The reaction was exothermic in nature. The rate of addition was regulated so as to maintain a relatively low temperature to avoid excessive color loss. The dimethyl sulfate addition required approximately 30 minutes.

Freeze-thaw stabilized quaternary ammonium chloride comopnd was prepared by mixing 70 parts of a dimethyl dihydrogenated tallow ammonium chloride composition 4 called Adogen 442, at 75% solids with 30 parts of the dimethyl sulfate salt of dicoco amine at 75% solids. The resulting mixture was then diluted with water to form a 6% dispersion in water. The 6% solid portion comprised 30% amine salt and 70% quaternary.

The freezing point of this mixture was about 32 F. The freeze-thaw stability of the mixture was determined by subjecting the 6% water dispersion to a temperature of 0 F. for 24 hours. The frozen solution was then allowed to thaw at room temperature. On thawing, the mixture was found to be a free-flowing solution. A sample of 6% dimethyl dihydrogenated tallow ammonium chloride in water was likewise subjected to the freezing and thawing. On thawing, the dimethyl dihydrogenated tallow ammonium chloride was found to be a gel, whereas previously it was a free-flowing liquid.

Example 11 Using the dimethyl sulfate salt of dicoco amine prepared in Example I, a mixture of parts of dimethyl dicoco ammonium chloride at 75% solids in isopropyl alcohol was mixed with 15 parts of the dimethyl sulfate salt of Example I at 75 solids. This mixture was dispersed in water at a 7% concentration based on the solids of the mixture. The mixture had a freezing point of about 32 F. The freeze-thaw stability was determined by subjecting the water solution to a temperature of 0 F. for 24 hours. The frozen solution was allowed to thaw at room temperature. On thawing, it was found that the solution was a free-flowing liquid and did not form the gel noted when the dimethyl sulfate salt was not present.

The softening properties of the quaternary ammonium chloride compound with dimethyl sulfate salt of an amine was determined both prior to freezing and after freezing and compared to the quaternary ammonium chloride compound which did not contain a sulfate salt. The softening properties were not detrimentally affected by the addition of the sulfate salt, nor did the freezing and subsequent thawing affect the performance of the composition.

Example III A freeze-thaw stabilized quaternary ammonium chloride compound was prepared by forming the sulfate salt of an amine in admixture with a quaternary ammonium chloride compound.

The composition was prepared by mixing 80 parts of Adogen 442, a dimethyl dihydrogenated tallow quaternary ammonium chloride compound at 75 solids in isopropyl alcohol, with 15 parts of dicoco amine. The mixing was accomplished by heating the quaternary and amine to a temperature of 110 F. at which temperature they were in the liquid state. While maintaining a temperature of 110 F., 6.0 parts of dimethyl sulfate was slowly added to the mixture. A slight exothermic reaction was noted. The addition of the dimethyl sulfate produced a salt of the dicoco amine.

The prepared composition exhibited freeze-thaw stability wren diluted with water so as to obtain a dispersion of 3% to about 8% solids.

Example IV A sulfate salt was prepared by reacting equal molar amounts of dimyristyl amine with diethyl sulfate. This was accomplished by dissolving 56 parts of dimyristyl amine in 25 parts of isopropyl alcohol. This was readily accomplished by heating the mixture to about F. The solution was placed in a reaction flask equipped with a stirring means, a thermometer, a cooling means, and a dropping funnel. The temperature was controlled so as to be within the range of F. to a maximum of F. while 19 parts of diethyl sulfate was slowly metered into the reaction flask. The reaction was exothermic. The diethyl sulfate addition required approxi mately 20 minutes.

The diethyl sulfate salt of dimyristyl amine prevented gel formation in quaternary ammonium chloride compounds which were subjected to freezing and thawing when the sulfate salt was used in a proportion of 8% up to about 50% based on the weights of quaternary ammonium chloride compound dispersed in a Water solution of about 3% to about 7% solids.

Example V The dimethyl sulfate salt of primary hydrogenated tallow amine was prepared by the addition of an equal molar amount of diethyl sulfate to the primary amine. The reaction was carried out at 120 -F. with a solution of 56 parts of hydrogenated tallow amine and 25 parts of isopropyl alcohol. The amine solution was placed in a reaction vessel equipped with a stirring means, a thermometer, a cooling means, and a dropping funnel. About 19 parts of dimethyl sulfate was metered into the amine solution while controlling the termperature between 120 F. and 150 F. An exothermic reaction was noted.

The dimethyl sulfate salt of hydrogenated tallow amine was found to exhibit the desired freeze-thaw stabilizing effect to quaternary ammonium chloride compounds when used in a stabilizing amount and dispersed in water solutions to obtain about 3% to 8% solids.

Example VI The diethyl sulfate salt of dimyristyl amine prepared in Example IV was used to achieve a freeze-thaw stabilized water solution of methyl tri-hydrogenated tallow quaternary ammonium chloride. This was accomplished by mixing 20 parts of the sulfate salt of Example IV with 80 parts of 75% methyl tri-hydrogenated tallow ammonium chloride in isopropyl alcohol. A water solution of this mixture was prepared by dispersing 7 parts of the mixture in 94 parts of water. The water solution exhibited the desired freeze-thaw stability.

The embodiment of the present invention in which an exclusive property or privilege is claimed are defined as follows:

1. A composition consisting essentially of a major amount of a fatty quaternary ammonium chloride compound and a minor amount sufficient to impart freezethaw stability to the composition of a dialkyl sulfate salt of a fatty amine, said fatty quaternary ammonium chloride compound having the formula:

wherein R is selected from the group consisting of alkyl, arylalkyl and cycloalkyl, having saturated or unsaturated hydrocarbon chains of 12 to 26 carbon atoms, R and R are selected from the group consisting of R and alkyl of 1 to 8 carbon atoms, and R is an alkyl of 1 to 8 carbon atoms, and said dialkyl sulfate salt of a fatty amine having the formula:

wherein R is selected from the group consisting of saturated and ethylenically unsaturated alkyls of 8 to 26 carbon atoms, R is selected from the group consisting of hydrogen and saturated or unsaturated alkyls of 1 to 26 carbon atoms and R and R" are alkyls of 1 to 8 carbon atoms.

2. A composition consisting essentially of a major amount of a fatty quaternary ammonium chloride, compound and a minor amount greater than 8% by weight of a dialkyl sulfate salt of a fatty amine, said fatty qua-ternary ammonium chloride compound having the formula:

wherein R is selected from the group consisting of alkyl, arylalkyl and cy-cloalkyl, having saturated or unsaturated hydrocarbon chains of 12 to 26 carbon atoms, R; and R are selected from the group consisting of R and alkyl of 1 to 8 carbon atoms, and R is an alkyl of 1 to 8 carbon atoms, and said dialkyl sulfate salt of a fatty amine having the formula:

wherein R is selected from the group consisting of saturated and ethylenically unsaturated alkyls of 8 to 26 carbon atoms, R is selected from the group consisting of hydrogen and saturated or unsaturated alkyls of 1 to 26 atoms and R and R are alkyls of l to 8 carbon atoms.

3. The composition of claim 2 wherein the amount of fatty quaternary ammonium chloride compound is 50 to 92% by weight of the composition and the amount of dialkyl sulfate salt of fatty amine is 8 to 50% by weight of the composition.

4. A composition consisting essentially of 92 to 97% by weight water and 3 to 8% by weight of a mixture in an alcholic solvent of 8 to 50% by weight of a dialkyl salt of a fatty amine and 50 to 92% by weight of a fatty quaternary ammonium chloride compound, said fatty quaternary ammonium chloride compound having the formula:

R2 [Ril lRz:lClin wherein R is selected from the group consisting of alkyl, arylalkyl and cycloalkyl, having saturated or unsaturated hydrocarbon chains of 12 to 26 carbon atoms, R and R are selected from the group consisting of R and alkyl of 1 to 8 carbon atoms, and R is an alkyl of 1 to 8 carbon atoms, and said dialkyl sulfate salt of a fattty amine having the formula:

wherein R is selected from the group consisting of saturated and ethylenically unsaturated alkyls of 8 to 26 carbon atoms, R is selected from the group consisting of hydrogen and saturated or unsaturated alkyls of 1 to 26 carbon atoms and R and R" are alkyls of 1 to 8 carbon atoms.

5. The composition of claim 4 wherein the dialkyl sulfate salt is the dimethyl sulfate salt of dicoco amine.

6. The composition of claim 5 wherein the ammonium chloride compound is dimethyl dihydrogenated tallow ammonium chloride.

References Cited by the Examiner UNITED STATES PATENTS 3,154,489 10/1964 De Brow et al 252-875 LEON D. ROSDOL, Primary Examiner.

JULIUS GREENWALD, Examiner.

I. T. FEDIGAN, Assistant Examiner. 

1. A COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF A FATTY QUATERNARY AMMONIUM CHLORIDE COMPOUND AND A MINOR AMOUNT SUFFICIENT TO IMPART FREEZETHAW STABILITY TO THE COMPOSITION OF A DIALKYL SULFATE SALT OF A FATTY AMINE, SAID FATTY QUATERNARY AMMONIUM CHLORIDE COMPOUND HAVING THE FORMULA: 